def get_breadcrumb(category):
    """
    获取面包屑导航
    :param category: 类别对象　一级，二级，三级，
    :return: 一级：返回一级．　二级：返回一级和二级．　三级：返回一级二级和三级
    """
    breadcrumb = {
        'cat1': '',
        'cat2': '',
        'cat3': '',
    }
    if category.parent == None:  # 说明category是一级
        breadcrumb['cat1'] = category
    elif category.subs.count() == 0:    # 说明category是三级
        cat2 = category.parent
        breadcrumb['cat1'] = cat2.parent
        breadcrumb['cat2'] = cat2
        breadcrumb['cat3'] = category
    else:   # 说明category是二级
        breadcrumb['cat1'] = category.parent
        breadcrumb['cat2'] = category

    return breadcrumb